/**
 * 最简单的基于FFmpeg的视频播放器 2
 * Simplest FFmpeg Player 2
 *
 * 雷霄骅 Lei Xiaohua
 * leixiaohua1020@126.com
 * 中国传媒大学/数字电视技术
 * Communication University of China / Digital TV Technology
 * http://blog.csdn.net/leixiaohua1020
 *
 * 第2版使用SDL2.0取代了第一版中的SDL1.2
 * Version 2 use SDL 2.0 instead of SDL 1.2 in version 1.
 *
 * 本程序实现了视频文件的解码和显示(支持HEVC，H.264，MPEG2等)。
 * 是最简单的FFmpeg视频解码方面的教程。
 * 通过学习本例子可以了解FFmpeg的解码流程。
 * This software is a simplest video player based on FFmpeg.
 * Suitable for beginner of FFmpeg.
 *
 */

#include <stdio.h>

#define __STDC_CONSTANT_MACROS

#ifdef _WIN32
// Windows
extern "C"
{
#include "libavcodec/avcodec.h"
#include "libavformat/avformat.h"
#include "libswscale/swscale.h"
#include "libavutil/imgutils.h"
#include "SDL2/SDL.h"
};
#else
// Linux...
#ifdef __cplusplus
extern "C"
{
#endif
#include <libavcodec/avcodec.h>
#include <libavformat/avformat.h>
#include <libswscale/swscale.h>
#include <SDL2/SDL.h>
#include <libavutil/imgutils.h>
#ifdef __cplusplus
};
#endif
#endif

// Output YUV420P data as a file
#define OUTPUT_YUV420P 0

int simplest_ffmpeg_player_standard_sdl2(void)
{
    // FFMPEG--------------------------
    AVFormatContext *pFormatCtx;
    int i, videoindex;
    AVCodecContext *pCodecCtx;
    AVCodec *pCodec;
    AVFrame *pFrame, *pFrameYUV;
    unsigned char *out_buffer;
    AVPacket *packet;
    int y_size;
    int ret, got_picture;
    struct SwsContext *img_convert_ctx;

    char filepath[] = "resource/nwn.mp4";
    // SDL---------------------------
    int screen_w = 0, screen_h = 0;
    SDL_Window *screen;
    SDL_Renderer *sdlRenderer;
    SDL_Texture *sdlTexture;
    SDL_Rect sdlRect;

    FILE *fp_yuv;

    av_register_all();                     // 注册所有组件
    avformat_network_init();               // 初始化网络库 可以打开rtsp http协议的流媒体视频
    pFormatCtx = avformat_alloc_context(); // 解封装上下文

    // 打开输入视频文件
    if (avformat_open_input(&pFormatCtx, filepath, NULL, NULL) != 0)
    {
        printf("Couldn't open input stream.\n");
        return -1;
    }
    // 获取视频文件信息
    if (avformat_find_stream_info(pFormatCtx, NULL) < 0)
    {
        printf("Couldn't find stream information.\n");
        return -1;
    }
    videoindex = -1; // 一般0是视频流
    for (i = 0; i < pFormatCtx->nb_streams; i++)
        if (pFormatCtx->streams[i]->codec->codec_type == AVMEDIA_TYPE_VIDEO)
        {
            videoindex = i;
            break;
        }
    if (videoindex == -1)
    {
        printf("Didn't find a video stream.\n");
        return -1;
    }

    pCodecCtx = pFormatCtx->streams[videoindex]->codec;
    // 查找解码器
    pCodec = avcodec_find_decoder(pCodecCtx->codec_id);
    if (pCodec == NULL)
    {
        printf("Codec not found.\n");
        return -1;
    }
    // 打开解码器
    if (avcodec_open2(pCodecCtx, pCodec, NULL) < 0)
    {
        printf("Could not open codec.\n");
        return -1;
    }

    pFrame = av_frame_alloc();
    pFrameYUV = av_frame_alloc();
    out_buffer = (unsigned char *)av_malloc(av_image_get_buffer_size(AV_PIX_FMT_YUV420P, pCodecCtx->width, pCodecCtx->height, 1));
    av_image_fill_arrays(pFrameYUV->data, pFrameYUV->linesize, out_buffer,
                         AV_PIX_FMT_YUV420P, pCodecCtx->width, pCodecCtx->height, 1);

    packet = (AVPacket *)av_malloc(sizeof(AVPacket));
    // Output Info-----------------------------
    printf("--------------- File Information ----------------\n");
    av_dump_format(pFormatCtx, 0, filepath, 0);
    printf("-------------------------------------------------\n");
    img_convert_ctx = sws_getContext(pCodecCtx->width, pCodecCtx->height, pCodecCtx->pix_fmt,
                                     pCodecCtx->width, pCodecCtx->height, AV_PIX_FMT_YUV420P, SWS_BICUBIC, NULL, NULL, NULL);

#if OUTPUT_YUV420P
    fp_yuv = fopen("output.yuv", "wb+");
#endif

    if (SDL_Init(SDL_INIT_VIDEO | SDL_INIT_AUDIO | SDL_INIT_TIMER))
    {
        printf("Could not initialize SDL - %s\n", SDL_GetError());
        return -1;
    }

    screen_w = pCodecCtx->width;
    screen_h = pCodecCtx->height;
    // SDL 2.0 Support for multiple windows
    screen = SDL_CreateWindow("Simplest ffmpeg player's Window", SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED,
                              screen_w, screen_h,
                              SDL_WINDOW_OPENGL);

    if (!screen)
    {
        printf("SDL: could not create window - exiting:%s\n", SDL_GetError());
        return -1;
    }

    sdlRenderer = SDL_CreateRenderer(screen, -1, 0);
    // IYUV: Y + U + V  (3 planes)
    // YV12: Y + V + U  (3 planes)
    sdlTexture = SDL_CreateTexture(sdlRenderer, SDL_PIXELFORMAT_IYUV, SDL_TEXTUREACCESS_STREAMING, pCodecCtx->width, pCodecCtx->height);

    sdlRect.x = 0;
    sdlRect.y = 0;
    sdlRect.w = screen_w;
    sdlRect.h = screen_h;

    // SDL End----------------------
    // 从输入文件读取一帧压缩数据
    while (av_read_frame(pFormatCtx, packet) >= 0)
    {
        if (packet->stream_index == videoindex)
        {
            ret = avcodec_decode_video2(pCodecCtx, pFrame, &got_picture, packet);   //解压一帧压缩数据
            if (ret < 0)
            {
                printf("Decode Error.\n");
                return -1;
            }
            if (got_picture)
            {
                sws_scale(img_convert_ctx, (const unsigned char *const *)pFrame->data, pFrame->linesize, 0, pCodecCtx->height,
                          pFrameYUV->data, pFrameYUV->linesize);

#if OUTPUT_YUV420P
                y_size = pCodecCtx->width * pCodecCtx->height;
                fwrite(pFrameYUV->data[0], 1, y_size, fp_yuv);     // Y
                fwrite(pFrameYUV->data[1], 1, y_size / 4, fp_yuv); // U
                fwrite(pFrameYUV->data[2], 1, y_size / 4, fp_yuv); // V
#endif
                // SDL---------------------------
#if 0
				SDL_UpdateTexture( sdlTexture, NULL, pFrameYUV->data[0], pFrameYUV->linesize[0] );
#else
                SDL_UpdateYUVTexture(sdlTexture, &sdlRect,
                                     pFrameYUV->data[0], pFrameYUV->linesize[0],
                                     pFrameYUV->data[1], pFrameYUV->linesize[1],
                                     pFrameYUV->data[2], pFrameYUV->linesize[2]);
#endif

                SDL_RenderClear(sdlRenderer);
                SDL_RenderCopy(sdlRenderer, sdlTexture, NULL, &sdlRect);
                SDL_RenderPresent(sdlRenderer);
                // SDL End-----------------------
                // Delay 40ms
                SDL_Delay(40);
            }
        }
        av_free_packet(packet);
    }
    // flush decoder
    // FIX: Flush Frames remained in Codec
    while (1)
    {
        ret = avcodec_decode_video2(pCodecCtx, pFrame, &got_picture, packet);
        if (ret < 0)
            break;
        if (!got_picture)
            break;
        sws_scale(img_convert_ctx, (const unsigned char *const *)pFrame->data, pFrame->linesize, 0, pCodecCtx->height,
                  pFrameYUV->data, pFrameYUV->linesize);
#if OUTPUT_YUV420P
        int y_size = pCodecCtx->width * pCodecCtx->height;
        fwrite(pFrameYUV->data[0], 1, y_size, fp_yuv);     // Y
        fwrite(pFrameYUV->data[1], 1, y_size / 4, fp_yuv); // U
        fwrite(pFrameYUV->data[2], 1, y_size / 4, fp_yuv); // V
#endif
        // SDL---------------------------
        SDL_UpdateTexture(sdlTexture, &sdlRect, pFrameYUV->data[0], pFrameYUV->linesize[0]);
        SDL_RenderClear(sdlRenderer);
        SDL_RenderCopy(sdlRenderer, sdlTexture, NULL, &sdlRect);
        SDL_RenderPresent(sdlRenderer);
        // SDL End-----------------------
        // Delay 40ms
        SDL_Delay(40);
    }

    sws_freeContext(img_convert_ctx);

#if OUTPUT_YUV420P
    fclose(fp_yuv);
#endif

    SDL_Quit();

    av_frame_free(&pFrameYUV);
    av_frame_free(&pFrame);
    avcodec_close(pCodecCtx);
    avformat_close_input(&pFormatCtx);

    return 0;
}
